Vaping — the use of electronic cigarettes — is one of the most contested public-health topics of the past decade. In the UK, public health authorities have endorsed vaping as a quit-smoking aid. In the US, the FDA and CDC have taken a more cautious tone. For people with schizophrenia, who smoke at much higher rates and bear a disproportionate share of smoking-related premature death, the question matters more than for most populations.
Vaping is almost certainly less harmful than smoking combustible cigarettes for most measured outcomes — but it is not harmless, and dual use offers very little benefit.
What vaping is, briefly
An e-cigarette heats a liquid containing nicotine, propylene glycol, vegetable glycerine, and flavourings to produce an inhalable vapour. There is no combustion, which means no tar and dramatically less carbon monoxide and benzene than a cigarette. The nicotine content varies enormously, from low-strength refillable systems to high-strength disposable pods that can deliver more nicotine per puff than a cigarette.
What we know about relative harm
The most influential review remains the 2018 evidence update by Public Health England, which concluded that e-cigarettes are "around 95 percent less harmful than smoking" — a figure heavily cited and heavily criticised. Subsequent reviews from the World Health Organization have been more reserved, noting that long-term safety data is limited and that vaping is clearly not risk-free. Both perspectives can be true. The current consensus is roughly:
- For someone who already smokes — switching completely to vaping substantially reduces exposure to combustion-related toxins and is likely to reduce cancer, cardiovascular, and respiratory risk over time.
- For someone who does not smoke — vaping is not safe, particularly for adolescents, and should not be started.
- For dual users — people who keep smoking and add vaping — most of the benefit of switching is lost.
The Cochrane evidence on cessation
The 2024 update of the Cochrane review of e-cigarettes for smoking cessation by Hartmann-Boyce and colleagues found "high-certainty evidence" that nicotine e-cigarettes increase quit rates compared with NRT alone, and "moderate-certainty evidence" that they outperform behavioural support alone. This is the strongest endorsement vaping has received from a major systematic review body. It does not mean vaping is risk-free — it means that for someone who has not been able to quit with NRT or counselling, vaping is a reasonable next step.
What about schizophrenia specifically?
Direct trial evidence in schizophrenia is limited. A small Italian study by Caponnetto and colleagues (European Addiction Research, 2013) followed 14 people with schizophrenia who were given e-cigarettes; about half reduced cigarette consumption by more than 50 percent at one year, and there were no negative effects on psychiatric symptoms. Larger pragmatic trials are ongoing. The more important data point is mechanistic: nicotine itself does not appear to worsen psychotic symptoms, and removing combustion products is biologically likely to benefit cardiovascular and respiratory outcomes that drive premature mortality in this population.
The CYP1A2 question
The CYP1A2-inducing effect that lowers clozapine and olanzapine levels is caused by polycyclic aromatic hydrocarbons in tobacco smoke — not by nicotine. Switching from cigarettes to vaping removes the smoke and therefore raises levels of these medications, sometimes substantially. Tell your prescriber before switching so they can plan a dose review and, for clozapine, a level check.
The risks worth taking seriously
EVALI
The 2019 outbreak of e-cigarette or vaping product use-associated lung injury (EVALI) was traced almost entirely to vitamin E acetate in unregulated THC vape cartridges, not to commercial nicotine vapes. Sticking to regulated nicotine products substantially reduces this risk.
Nicotine dependence
High-strength pod systems (such as those delivering 5 percent nicotine salts) can produce dependence quickly, sometimes more rapidly than cigarettes. Some users find themselves vaping more total nicotine per day than they previously smoked.
Long-term respiratory effects
Vaping is associated with increased rates of cough, wheeze, and asthma exacerbation. The long-term cancer risk appears much lower than smoking but is not zero, and decades-long data simply do not yet exist.
Cardiovascular effects
Acute exposure raises heart rate and blood pressure. Long-term cardiovascular harm appears smaller than smoking but again is not fully characterised.
Practical guidance
If you smoke and have not been able to quit with NRT or varenicline, switching completely to a regulated nicotine vape is a reasonable harm-reduction step. The keyword is completely. Things that improve the odds:
- Use a regulated commercial product, not unregulated mods or grey-market cartridges.
- Choose a nicotine strength high enough to suppress cravings — too low a dose drives people back to cigarettes.
- Set a target end date for vaping if possible. Some people taper off; others use it indefinitely.
- Coordinate with your prescriber if you are on clozapine, olanzapine, or several other antipsychotics.
- Avoid vaping THC or CBD products from informal sources.
What if you don't smoke?
Don't start. There is no scenario in which someone who has never smoked benefits from picking up vaping. The brief cognitive effects of nicotine in schizophrenia (see our deep article) do not justify initiating a new dependence with its own physical and financial costs.
The honest bottom line
Vaping is best understood as a harm-reduction tool for people who already smoke and have not been able to quit with first-line methods. It is not a "safe" alternative to be promoted in absolute terms. For someone with schizophrenia who has been smoking heavily for years and has cardiovascular or respiratory disease accumulating, switching completely is likely to be a meaningful step forward. The decision belongs to you and your clinician.
This article is for educational purposes only and is not medical advice, diagnosis, or treatment. Always consult a qualified mental health professional. If you or someone you know is in crisis, call or text 988 in the US, or your local emergency number.